Startup Time in the Wild Take Two

This week, I spent some time looking at some real life profiles that were sent into us by users seeing startup time in the minutes. The tests were ran just like I ran the test on my profile: all add-ons disabled. The results I got are both good and bad, but first the results!


The first shows the raw test run data (which isn’t terribly interesting). The second compares the reported startup time for each test. You will probably want to click to zoom in.


Like I said, the results are both good and bad. Good in that I now have a pretty good idea on why people have bad startup times. Bad in that we don’t have any way to quickly improve the issues that people are seeing. What I see from this data is that profiles in the wild, with add-ons disabled aren’t much slower than a clean profile. This seems to implicate add-ons being at least part of the problem (which we knew) or possibly all of the problem at this point (for the profiles tested). The good news is that the add-ons team is already working on solutions to this, and you should expect some blog posts from them about this soon.

Next Step

Next week I’m going to spend some time getting numbers with these profiles on the latest release of Firefox 3.6 with and without add-ons disabled to compare. This will pretty much confirm or deny my hypothesis of this week’s results.

News on the Past

In my last post, we looked at my profile with various pieces removed to try and figure out why startup might be slow for people. With those results, I identified two issues that would impact startup the most:

  1. Large cookies.sqlite
  2. Many tabs being restored

I also have good news about both of these issues! The cookies.sqlite issue is now fixed and will be a part of beta 4, and Paul has some good data about session restore and tabs (with more to come).

By Shawn Wilsher

The man behind the site.

7 replies on “Startup Time in the Wild Take Two”

It’d like to note that this is a very synthetic test. This measures these bad profiles under optimum conditions and is doing warm startup at that.

Cold startup will vary more and will be even worse due to real-life sqlite fragmentation. Measuring warm startup with large profiles is very suboptimal since loading those profiles into cache is what hurts most.

As to addons being bad, we really need to implement bug 558200 to help addon authors diagnose their extensions.

You’re going to test it for yourself anyway, but my guess would be that the reason the profiles have gone from 60s to 0.5s startup time is not the lack of add-ons, but the fact that they’re running on a different computer.

Also, were these users seeing warm start times of 60 seconds, or cold start times? All the non-techie Windows XP users I know shut down their computers rather than using sleep or hibernate…

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